Cleanup GpuMemoryBuffer

content/common/gpu/client/gpu_channel_host.h

Index: content/common/gpu/client/gpu_channel_host.h
diff --git a/content/common/gpu/client/gpu_channel_host.h b/content/common/gpu/client/gpu_channel_host.h
index ad56d18d85a13aca16672a2eb0d79794a3808277..ea988997b3f7d349e1f0d59bbae443fd7f7a1bc0 100644
--- a/content/common/gpu/client/gpu_channel_host.h
+++ b/content/common/gpu/client/gpu_channel_host.h
@@ -75,6 +75,8 @@ class CONTENT_EXPORT GpuChannelHostFactory {
       int32 surface_id,
       const GPUCreateCommandBufferConfig& init_params,
       int32 route_id) = 0;
+  virtual void WaitForPendingGpuMemoryBufferUsageToComplete(
+      const base::Closure& callback) = 0;
 };
 
 // Encapsulates an IPC channel between the client and one GPU process.
@@ -161,6 +163,9 @@ class GpuChannelHost : public IPC::Sender,
   // Generate a route ID guaranteed to be unique for this channel.
   int32 GenerateRouteID();
 
+  void WaitForPendingGpuMemoryBufferUsageToComplete(
+      const base::Closure& callback);
+
  private:
   friend class base::RefCountedThreadSafe<GpuChannelHost>;
   GpuChannelHost(GpuChannelHostFactory* factory,
@@ -242,6 +247,17 @@ class GpuChannelHost : public IPC::Sender,
   typedef base::hash_map<int, CommandBufferProxyImpl*> ProxyMap;
   ProxyMap proxies_;
 
+  void WaitForPendingGpuMemoryBufferUsageToCompleteOnMain(
+      uint32 id,
+      scoped_refptr<base::MessageLoopProxy> caller_message_loop);
+  void WaitCompletedOnCallerThread(uint32 id);
+
+  // Protects signal_tasks_.
+  mutable base::Lock signal_lock_;
+  typedef base::hash_map<uint32, base::Closure> SignalTaskMap;
+  SignalTaskMap signal_tasks_;
+  uint32 next_signal_id_;
+
   DISALLOW_COPY_AND_ASSIGN(GpuChannelHost);
 };